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1

Review the gait cycle

Phases: normal gait cycle is divided into stance and swing phases (see Fig. 10.1).

Stance phase occupies 60% of the gait cycle.

Initial contact (IC): the instant the reference foot contacts the ground

Loading response (LR) starts with initial contact of reference foot and ends with initial swing of the contralateral foot.

Midstance (MSt) begins with initial swing (ISw) of the advancing foot and ends when the body’s center of gravity is directly over the supporting forefoot.

Terminal stance (TSt) begins with heel rise and continues until initial contact of the contralateral (advancing) foot.

Preswing (PSw) begins with initial contact of contralateral limb and ends when the stance foot lifts off the ground.

Swing phase is 40% of the gait cycle.

Initial swing (ISw) begins when the reference foot leaves the ground, and ends when the swinging foot is opposite the stance foot.

Midswing (MSw) ends when the swinging limb is forward with the tibia perpendicular/vertical to ground.

Terminal swing (TSw) spans the period from when the advancing limb’s tibia is perpendicular/vertical to ground to when the foot makes initial contact with the ground (Fig. 10.3).

Important characteristics of gait cycle

Normal gait cycle requires stance-phase stability, swing-phase ground clearance, correct position of the foot before initial contact, and energy-efficient step length and speed.

There are two periods of double-limb support (during IC + LR and then PSw) ranging between 20% and 30% of the gait cycle. Time spent in these events is velocity dependent.

During normal walking, the body’s center of gravity is subject to vertical and lateral displacement. Minimizing trunk displacement decreases energy expenditure during bipedal gait.

In the sagittal plane of the body, vertical displacement follows a sinusoidal curve with an amplitude of 5 cm.

Lateral displacement also follows a sinusoidal curve, with an amplitude of 6 cm.

2

What is the difference between a step and a stride?

velocity is distance over time

cadence is steps over time

3

Kinematics of the Gait Cycle

4

Graph overview of the walking cycle

5

Review the 6 determinants of Gait:

Six principal processes have been identified as determinants of gait efficiency, working in concert to minimize vertical and lateral displacements of the center of mass during typical walking. Three occur at the pelvis, and the others involve the knee, ankle, and foot mechanisms.

Pelvic rotation: During forward motion, the pelvis externally rotates from IC to onset of PSw, and internally during PSw and swing. This symmetric net rotation minimizes the total vertical plane displacement needed for limb retraction and advancement in swing and stance.

Pelvic list (tilt): non–weight-bearing contralateral side drops 5 degrees, reducing superior deviation.

Knee flexion at loading (early knee flexion): stance-phase limb is flexed 15 degrees to dampen the impact of initial loading.

Foot and ankle motion: through subtalar joint, damping of loading response occurs, leading to stability during midstance and efficiency of propulsion at push-off.

Knee motion: knee works in concert with foot and ankle to decrease unnecessary limb motion. The knee flexes at IC and extends at midstance.

Control of pelvic lateral displacement: occurs during weight transfer of body onto the accepting/leading limb. Length of motion is 5 cm over the weight-bearing limb, narrowing the base of support and increasing stance-phase stability.

6

Major Muscle movements with Gait

Agonist and antagonist muscle groups work in concert during the gait cycle to effectively advance the limb through space.

Most muscle activity is eccentric, during which a muscle is active while lengthening (aka elongation), oftentimes working in concert with an antagonist muscle to control joint and limb segment motion (Table 10.1).

In isometric contraction, muscle length remains constant during contraction.

Some muscle activity can be concentric, in which the muscle shortens to move a joint through space.

Hip flexors advance the limb forward during swing phase, and the motion trajectory of the advancing limb is fine tuned by the decelerating action of the hip extensors during terminal swing and before IC.

The anterior tibialis has both eccentric (IC) and concentric (swing) muscle actions during normal gait. The posterior tibialis inverts the hindfoot and locks the transverse tarsal joints in the terminal stance to facilitate the heel rise and toe-off by the gastrocnemius muscles.

7

Gait Pearls

Muscle weakness or paralysis: decreases ability to control joint movement. Walking strategies develop on the basis of the specific muscle or muscle groups involved and the ability of the individual to execute adaptation—that is, effective substitutions replacing or compensating for deficient muscle action(s).

Neurologic conditions: may alter gait by producing muscle weakness, loss of balance, reduced coordination between agonist and antagonist muscle groups (i.e., spasticity), and joint contracture.

Hip scissoring is associated with overactive adductors, and knee flexion may be caused by hamstring spasticity or knee extensor weakness.

Equinus deformity of the foot and ankle may result in steppage gait (exaggerated knee flexion through swing, to effect clearance for the advancing limb) and hyperextension moment through the knee during stance phase.

Pain in a limb: creates an antalgic gait pattern in which the individual shortens stance phase to lessen the time the painful limb is loaded. The contralateral swing phase is more rapid.

Joint abnormalities: alter gait by changing the range of motion of the affected joint or producing pain.

A hip and knee with arthritis may have joint contractures and reduced range of motion.

An anterior cruciate–deficient knee has quadriceps-avoidance gait, which represents a decreased quadriceps moment during midstance. The patient compensates with forward flexion of the trunk, plantar flexion of the ankle, and sometimes use of the hand to hyperextend the knee.

Hemiplegia: characterized by prolongation of stance and double-limb support

Gait impairment may consist of excessive plantar flexion, weakness, and balance problems.

Associated problems are ankle equinus, limitation of knee flexion, and increased hip flexion.

Crutches and canes: devices that ameliorate instability and pain

Crutches increase stability by providing two additional load points.

A cane helps shift the center of gravity to the affected side when the cane is used in the opposite hand. This shift decreases the joint reaction of the lower limb and reduces the pain. (See Chapter 5, Adult Reconstruction.)

Arthritis: forces across knee may be four to seven times those of the body weight; 70% of load across knee occurs through medial compartment.

Water walking: significant decrease in joint moments and total joint contact forces due to buoyancy

8

Metabolic cost of amputation

9

List of amputations and locations

10

Review upper extremity Amputations

Hand amputation

Transphalangeal, transmetacarpal, or transcarpal

Thumb opposition is the most important component of hand function.

Thumb reconstruction procedures include phalangization (deepening the web space to provide more mobile digits) and pollicization (moving a finger with its nerve and vessels to the site of an amputated thumb).

Wrist disarticulation

Advantages

Wrist disarticulation has two advantages over transradial amputation.

Preservation of full elbow motion and forearm rotation because of preservation of the distal radioulnar joint

Improved prosthetic suspension because of the flare of the distal radius

Effective function can be obtained at this level of amputation. Forearm rotation and strength are directly related to the length of the transradial (below-elbow) residual limb.

Disadvantages

Wrist disarticulation provides challenges to the prosthetist that may outweigh its benefits.

Cosmetic disadvantage

Prosthetic limb is longer than contralateral limb.

If myoelectric components are used, the motor and battery cannot be hidden within the prosthetic shank.

Transradial amputation or elbow disarticulation

Complete brachial plexus injury and a nonfunctioning hand and forearm may be best treated by a transradial amputation or elbow disarticulation, which can be fitted with a prosthesis.

The length of residual limb is a major determinant of the strength of elbow flexion, the preservation of forearm rotation, and the degree of elbow and humerus needed for suspension. The optimal length of the residual limb is at the junction of the middle and distal thirds of the forearm, where the soft tissue envelope can be repaired by myodesis and the components of a myoelectric prosthesis can be hidden within the prosthetic shank.

Because the patient can maintain prosthetic function at this level only by being able to open and close the terminal device, retention of the elbow joint is essential.

Krukenberg amputation converts the ulna and radius into digits to provide prehensile function.

The length and shape of elbow disarticulation provides better suspension and lever-arm capacity than transradial amputation. To enhance suspension and reduce the need for shoulder harnessing, a 45- to 60-degree distal humeral osteotomy is performed.

Elbow disarticulation is recommended for growing children to preserve the epiphyseal plate and avoid bony overgrowth.

Elbow disarticulation poses prosthetic fitting challenges that result in a limb that is bulkier and longer than the sound limb.

Gangrene of the upper limb, when it is not due to Raynaud or Buerger disease, represents end-stage disease, especially in diabetic patients. Such patients usually do not survive beyond 24 months.

Localized finger amputations in these patients are unlikely to heal. When surgery becomes necessary, amputation should be performed at the transradial level to achieve wound healing during the final months of the patient’s life.

11

Review lower extremity amputations

Toe and ray amputations

Patients with ischemia generally ambulate with a propulsive gait pattern, so they suffer little disability from toe amputation.

Patients with traumatic amputations lose some stability after toe amputation in the late-stance phase.

The great toe should be amputated distal to the insertion of the flexor hallucis brevis.

Isolated second-toe amputation should be performed just distal to the proximal phalanx metaphyseal flare, leaving the stump to act as a buttress and prevent late hallux valgus.

Patients who undergo single outer (first or fifth) ray resections function well in standard shoes.

Resection of more than one ray leaves the forefoot narrow, which is difficult to fit in shoes and often results in a late equinus deformity.

Central ray resections are complicated by prolonged wound healing and rarely achieve better results than midfoot amputation.

Transmetatarsal and Lisfranc tarsal-metatarsal amputations

There is little functional difference in outcome between these two procedures. The long plantar flap acts as a myocutaneous flap and is preferred to fish-mouth dorsal-plantar flaps.

Transmetatarsal amputation should be performed through the proximal metaphyses to prevent late plantar pressure ulcers under the residual bone ends.

Percutaneous Achilles tendon lengthening should be performed with transmetatarsal and Lisfranc amputations to prevent late development of equinus or equinovarus deformity.

Late varus deformity can be corrected with transfer of the tibialis anterior tendon to the neck of the talus.

The second tarsometarsal joint should be osteotomized to preserve midfoot stability.

The soft tissue at the fifth metatarsal base should be preserved because it represents the insertion site of the peroneus brevis and tertius muscles, which act as antagonists to the posterior tibial tendon.

Failure to preserve these tissues results in inversion during gait.

Some writers have reported reasonable functional outcomes with hindfoot amputation (i.e., Chopart or Boyd amputation), but most experts recommend avoiding amputation at these levels if possible in patients with diabetes or vascular disease.

Although children have been reported to function reasonably well with transmetatarsal amputation alone, adults retain an inadequate lever arm and are prone to experience fixed equinus deformity of the heel if Achilles tendon lengthening and tibialis anterior tendon transfer are not also performed.

Ankle disarticulation (Syme amputation)

Often performed for forefoot trauma, this amputation allows direct load transfer and possible short-distance ambulation without a prosthesis. It is rarely complicated by late residual limb ulcers or tissue breakdown.

It provides a stable gait pattern that rarely necessitates prosthetic gait training after surgery.

The outcome is more energy efficient than that of a midfoot amputation, despite the fact that it is a more proximal level (commonly tested exception to the rule of energy efficiency and amputations).

Surgery should be performed in one stage, even in ischemic limbs with insensate heel pads.

The posterior tibial artery must be patent to ensure healing.

The malleoli and metaphyseal flares should be removed from the tibia and fibula, but the remaining tibial articular surface should be retained to provide a resilient residual limb.

The heel pad should be secured to the tibia either anteriorly through drill holes or posteriorly by securing the Achilles tendon.

Transtibial (below-knee) amputation

A long posterior myocutaneous flap is the preferred method of creating a soft tissue envelope, especially in patients with vascular disease, inasmuch as the direction of blood flow is from posterior to anterior.

The optimum bone length is at least 12 cm below the knee joint or longer if adequate amounts of the gastrocnemius or soleus muscle can be used to construct a durable soft tissue envelope.

The posterior muscle should be secured to the beveled anterior tibia by myodesis.

Rigid dressings are preferred during the early postoperative period, and early prosthetic fitting may be started, 5–21 days after surgery, if the residual limb is capable of transferring load and if the patient has a satisfactory physical reserve.

Knee disarticulation (through-knee amputation)

The current technique involves the use of a long posterior flap, with the gastrocnemius muscle as end padding.

The alternative is to use sagittal skin flaps and cover the end of the femur with the gastrocnemius muscle to act as a soft tissue envelope end pad.

The Mazet technique involves partial removal of the femoral condyles, an effective myodesis for the adductors as well as anterior and posterior compartment muscles, and appropriation of a partial patella in the intercondylar groove. The resultant residuum shape does not pose a challenge to fit, because it lacks the distal bulkiness/flaring otherwise present due to retained femoral condyles.

The patellar tendon is sutured to the cruciate ligaments in the notch, leaving the patella on the anterior femur.

This level is generally used in nonambulatory patients who can support wound healing at the transtibial or distal level.

Data from the Lower Extremity Assessment Project (LEAP) study have demonstrated that knee disarticulations result in the slowest walking speed and produce the least self-reported satisfaction.

Knee disarticulation is muscle balanced and provides an excellent weight-bearing platform for sitting and a lever arm for bed-to-chair transfer. When this type of amputation is performed in a potential walker, it provides a residual limb for direct bed-to-chair transfer (end bearing).

Transfemoral (above-knee) amputation

This form of amputation increases the energy cost for walking.

Patients with transfemoral amputations who have peripheral vascular disease are unlikely to become efficient walkers; thus salvaging the limb at the knee disarticulation (transtibial level) is crucial for maintaining functional walking independence.

With greater femoral length, the lever arm, suspension, and limb advancement are optimized. The optimum transfemoral bone length is 12 cm above the knee joint to accommodate the prosthetic knee.

Adductor myodesis is important for maintaining femoral adduction during the stance phase to allow optimal prosthetic function (Fig. 10.7).

The major deforming force is toward abduction and flexion. Adductor myodesis at normal muscle tension eliminates the problem of adductor roll in the groin. Transecting the adductor magnus results in a loss of 70% of the adductor pull (Fig. 10.8).

Rigid dressings are difficult to apply and maintain at this level. Elastic compression dressings are used and may be suspended about the opposite iliac crest.

Hip disarticulation

This procedure is infrequently performed, and of the patients who undergo this amputation, only a few make meaningful use of prostheses because of the high energy requirements of walking.

Patients who have suffered trauma or who have tumors occasionally use the prostheses for limited activity. These patients sit in their prostheses and must use the torso to achieve momentum for “throwing” the limb forward to advance it.

12

adbuctor arm values

Diagram of moment arms of the three adductor muscles (R1, R2, and R3). Loss of the distal attachment of the adductor magnus (AM) will result in a loss of 70% of the adductor pull. AB, Adductor brevis; AL, adductor longus.

13

Adductor magnus myotenodesis for transfemoral amputation

(A) Diagram showing attachment of the adductor magnus to the lateral part of the femur. (B) Diagram depicting attachment of the quadriceps over the adductor magnus.

14

Orthosis Review

The primary function of an orthosis is control of the motion of certain body segments.

Orthoses are used to protect long bones or unstable joints, support flexible deformities, and occasionally substitute for a functional task. They may be static, static progressive, or dynamic.

With few exceptions, orthoses are not indicated for correction of fixed deformities or for spastic deformities that cannot be easily controlled manually.

Orthoses are named according to the joints they control, the function they provide, and the method used to obtain or maintain that control (e.g., a short-leg, below-knee brace is an ankle-foot orthosis [AFO]).

Shoes

Specific shoes can be used by themselves or in conjunction with foot orthoses. The Blucher (open throat) and the Bal (closed throat) are the two types of shoes commonly worn. The Blucher type is better in terms of accommodating foot orthoses.

Extra-depth shoes with a high toe box designed to dissipate local pressures over bony prominences (such as claw deformities) and are recommended for diabetic patients.

The plantar surface of an insensate foot is protected by use of a pressure-dissipating material. A paralytic or flexible foot deformity can be controlled with more rigid orthoses.

SACH heels absorb the shock of initial loading and lessen the transmission of force to the midfoot as the foot passes through the stance phase.

A rocker sole can lessen the bending forces on an arthritic or stiff midfoot during midstance as the foot changes from accepting the weight-bearing load to pushing off. It is useful in treating metatarsalgia, hallux rigidus, and other forefoot problems. For the rocker sole to be effective, it must be rigid.

Medial heel out-flaring is used to treat severe flatfoot of most causes. A foot orthosis is also necessary.

Foot Orthoses

Most foot orthoses are used to align and support the foot; prevent, correct, or accommodate foot deformities; and improve foot function.

Three main types of foot orthosis are used: rigid, semirigid, and soft.

Rigid foot orthoses limit joint motion and stabilize flexible deformities.

Semirigid orthoses aim to provide some support as well as absorb shock.

Soft orthoses have the best shock-absorbing ability and are used to accommodate fixed deformities of the feet, especially neuropathic, dysvascular, and ulcerative disorders.

Ankle-Foot Orthoses

The most commonly prescribed lower limb orthosis (AFO) is used to control the ankle joint. It may be fabricated with metal bars attached to the shoe or with TPE. The orthosis may be rigid, preventing ankle motion, or it can allow free or spring-assisted motion in either plane.

After hindfoot fusions, the primary orthotic goals are absorption of GRF, protection of the fusion sites, and protection of the midfoot. In addition, AFOs are commonly prescribed for footdrop, plantar spasticity, and spinal cord injury.

The TPE foot section achieves mediolateral control of various degrees with different trimlines. Choice of full/anterior, intermediate, and posterior trimlines takes into consideration the intended function, level of control, as well as medical comorbidities, such as limb sensation and recurrent swelling.

When ankle motion is present, an articulating AFO permits motion through a mechanical ankle joint design.

Primary factors in selection of an orthotic joint include range of motion, durability, adjustability, and the biomechanical effect on the knee joint.

Knee-Ankle-Foot Orthosis

The knee-ankle-foot orthosis (KAFO) extends from the upper thigh to the foot. It is generally used to control an unstable knee joint. It provides mediolateral stability with the prescribed amounts of flexion or extension control.

The stability of knee joints in KAFOs can be provided by various designs and use of knee locks of different types.

A subset of KAFOs are knee orthoses, which can be used to relieve pain of knee osteoarthritis, stabilize the patella or ACL deficient knee, or facilitate postoperative rehabilitation.

Hip-Knee-Ankle-Foot Orthosis

The hip-knee-ankle-foot orthosis (HKAFO) provides hip and pelvic stability but is rarely used by paraplegic adults because of the cumbersome nature of the orthosis and the magnitude of effort in achieving minimal gains.

In experimental studies, it is being used in conjunction with implanted electrodes and the computerized functional stimulation of paraplegic patients.

In children with upper-level lumbar myelomeningocele, the reciprocating gait orthoses are modified HKAFOs that can be used for therapeutic upright activities and simulated walking as a complement to wheelchair use.

Elbow Orthosis

Hinged-elbow orthoses provide minimum stability in the treatment of ligament instability.

Dynamic spring-loaded orthoses have been successfully used in the treatment of flexion and extension contractures.

An elbow strap is used to treat lateral epicondylitis. In addition, a long arm splint with the elbow flexed at 45 degrees can be tried to treat cubital tunnel syndrome.

Wrist-Hand Orthosis

The most common use of wrist and hand orthoses (WHOs) today is for postoperative care after injury or reconstructive surgery. These devices can be static, static-progressive, or dynamic.

The opponens splint is successful in prepositioning the thumb but impairs tactile sensation.

Wrist-driven hand orthoses are used in patients with lower cervical quadriplegia. The devices may be body powered by tenodesis action or motor driven. Weight and cumbersomeness are the major limiting factors.

Fracture Braces

Fracture bracing remains a valuable treatment option for isolated fractures of the tibia and fibula.

Prefabricated fracture orthoses can be used in simple foot and ankle fractures, ankle sprains, and simple hand injuries.

Pediatric Orthoses

Many dynamic orthoses are used by children to control motion without total immobilization.

The Pavlik harness has become the mainstay for early treatment of developmental dislocation of the hip.

Several dynamic orthoses have been used for containment in Perthes disease.

Spine Orthoses

Cervical spine

Numerous orthoses are used to immobilize the cervical spine.

Effective immobilization options range from the various types of collars, to posted orthoses that gain purchase about the shoulders and under the chin, to the halo vest, which achieves the most stability by the nature of its fixation into the skull.

Thoracolumbar spine

Orthoses used to mechanically stabilize the back, thus reducing back pain, rely on three-point pressure mechanism and increasing body cavity pressure.

Three-point orthoses achieve their control through the length of their lever arm and the subsequent limitation of motion.

15

Transfemoral Gait abnormalities

16

Transtibial Gait Abnormalities 

swing-phase pistoning 

ineffective suspension system

stance-phase pistoning 

poor socket fit

stump volume changes (stump sock may need to be changed)

foot alignment abnormalities inset foot 

varus strain, circumduction and pain

outset foot 

valgus strain, broad-based gait and pain

anterior foot placement 

stable increased knee extension with patellar pain

posterior foot placement 

unstable increased knee flexion

dorsiflexed foot 

increased patellar pressure

plantar-flexed foot 

drop-off and increased patellar pressure

pain or redness related to pressure

prosthetic foot abnormalities heel is too soft 

leads to excessive knee extension

heel is too hard 

leads to excessive knee flexion and lateral rotation of toes

17

Prothestic goals

The goal of prosthetics are to restore limb function to as close to original function

Requires a multidisciplinary team approach for coorindation of efforts to achieve the best outcome

Prosthetics upper limb 

limb salvage is ideal in the upper arm given lack of sensation with prosthetic

residual limb length is important for suspending prosthetic socket

lower limb 

goals for prosthetic are comfort, easy to get on and off, light, durable, cosmetic, and functional

18

General issue with prothesthics

choke syndrome 

caused by obstructed venous outflow due to a socket that is too snug

acute phase 

red, indurated skin with orange-peel appearance

chronic phase 

hemosiderin deposits and venous stasis ulcers

skin problems contact dermatitis 

most commonly caused by liner, socks, and suspension mechanism

treatment 

remove the offending item with symptomatic treatment

cysts and excess sweating 

signs of excess shear forces and improperly fitted components

scar 

massage and lubricate the scar for a well-healed incision

painful residual limb 

possible causes include heterotopic ossification, bony prominences, poorly fitting prostheses, neuroma formation, and insufficient soft tissue coverage

19

Review the 6 types of prosthethic knees

polycentric (four-bar linkage) knee indications 

transfemoral amputation

knee disarticulations

bilateral amputations

techniques 

variable knee center of rotation

controlled flexion

ability to walk at a moderately fast pace

supports increased weight compared to constant friction knee

stance-phase control (weight-activated) kneeindications 

older patients with proximal amputations

patients walking on uneven terrain

techniques 

acts like a constant-friction knee in swing phase

weightbearing through the prosthesis locks up through the high-friction housing

fluid-control (hydraulic and pneumatic) kneeindications 

active patients willing to sacrifice a heavier prosthesis for more utility and variability

techniques 

allows for variable cadence via a piston mechanism

prevents excess flexion

extends earlier in the gait cycle

constant friction (single axis) knee indications 

general use

patients walking on uneven terrain

most common pediatric prosthesis

not recommended for older or weaker patients

technique 

hinge that uses a screw or rubber pad to apply friction to the knee to decrease knee swing

only allows a single speed of walking

relies on alignment for stance phase stability

variable-friction (cadence control)technique 

multiple friction pads increase knee flexion resistance as the knee extends

variable walking speeds are allowed

not very durable

manual locking kneetechnique 

constant friction knee hinge with an extension lock

extension lock can be unlocked to allow knee to act like a constant-friction knee

Socket